Canine Gastric Tumor Study Guide

Overview and Clinical Importance

Gastric tumors in dogs represent less than 1% of all canine malignancies but carry significant clinical importance due to their late presentation, high metastatic rate, and poor prognosis. Understanding the various tumor types, their breed predispositions, diagnostic approaches, and treatment options is essential for the NAVLE examination and clinical practice. Most gastric tumors in dogs are malignant, with adenocarcinoma being the most common (42-72% of cases), followed by lymphoma, leiomyosarcoma, and gastrointestinal stromal tumors (GISTs).

Epidemiology and Etiology

General Characteristics

Gastric tumors most commonly affect older dogs (median age 8-10 years), with a male predilection (male-to-female ratio of 2-2.5:1). The etiology remains largely unknown, although chronic nitrosamine administration has been associated with gastric carcinoma development in experimental settings. A strong genetic component is suspected given the significant breed predispositions.

Breed Predispositions

Classification of Canine Gastric Tumors

1. Gastric Adenocarcinoma

Gastric adenocarcinoma is the most common malignant gastric tumor in dogs, accounting for 42-72% of gastric neoplasms. These tumors arise from the glandular epithelium of the gastric mucosa.